1. Field of the Invention
The present invention pertains to an improved cell for use in an improved impact attenuation device used to protect vehicles from striking concrete abutments, sign posts, guard rails and the like along the nation's highways and especially at the intersection of an exit lane of the highway.
2. Description of the Prior Art
There is an increasing need to provide an attenuator for use along highways and the like, either in front of abutments or between highway lanes, that crashing vehicles can safely be arrested and kept from impacting superstructures, barriers and the like which are adjacent thereto.
The Federal Highway Administration has approved many specific crash barrier systems for such highway application. Among these systems are the so-called steel drum and High-Dry Cell sandwich systems which dissipate energy, primarily through a sacrificial crushing of the structure thereof. The other approved systems generally fall within a class of crash cushions which dissipate energy largely by momentum transfer.
Such cushion-type crash barrier systems have been employed along the nation's highways since the 1960's. Such systems are intended to provide impact protection for obstacles such as roadway gores, tunnel entrances, as well as bridge and freeway abutments.
One such cushion-type barrier is that of Walker, Ford & Meinzer in U.S. Pat. No. 3,666,055, issued May 30, 1972 for an energy absorbing device using a block of vermiculite to dissipate or transform the impact energy by the disintegration of the vermiculite cell block.
Another crash cushion known to Applicant is that disclosed in Meinzer U.S. Pat. No. 4,101,115 which is also vermiculite based.
Such crash cushions can be used in various attenuating devices such as those disclosed in the aforesaid U.S. Pat. No. 4,101,115 patent, and in the patent of Walker U.S. Pat. No. 3,944,187 issued Mar. 16, 1976, among others.
There exists, therefore, a need for an improved crash cushion, capable of energy dissipation and with which significant quantities of energy absorption can be realized at relatively low crushing force. There also exists a need for an improved energy attenuation device that would employ such an improved crash cushion.
It is, therefore, an object of the instant invention to provide an improved vehicular impact absorption system which utilizes a new crash cushion.
It is another object to provide an improved, economical and practical impact absorption system particularly suited for use in protecting structures situated along the highway.
It is another object to provide in an impact absorption system having a plurality of aligned crash cushions with the capability of protecting highway abutments from impacting vehicles.
It is a further object to provide in a vehicular impact absorption system a cushion which is reliable in operation, economic to fabricate and easy to install and maintain.
A still further object is to provide a crash cushion having increased compressibility over prior art cushions.
These and other objects and advantages are achieved through the use of an impact absorption system characterized by a plurality of aligned crash cushions, each cushion of the plurality being formulated from a unique combination of urethane foam forming reactants disposed in a container.
These and other objects will become more readily apparent with references to the following description and claims in light of the accompanying drawings.